What was found
DURING CLIMBOUT, THE CREW REPORTED A PROBLEM WITH AIR LEAKING AROUND THE DOCUMENT DOOR. CREW THEN ELECTED TO RETURN TO DEN. AIRCRAFT LANDED IN DEN WITH NO FURTHER INCIDENT. MAINTENANCE INSPECTED THE DOCUMENT DOOR AND FOUND NO DISCREPANCIES. ALSO, CONDUCTED A GROUND OPERATIONAL CHECK OF THE PRESSURIZATION SYSTEM IAW AMM 21-31-00 COULD NOT DUPLICATE THE PROBLEM. THE AIRCRAFT WAS THEN RETURNED TO SERVICE. IT SHOULD BE NOTED, THE DOCUMENT DOOR WAS REPLACED THE FOLLOWING DAY, BECAUSE OF A SEAL FAILURE.